1. Field of the Invention
The present invention relates to a liquid ejecting head for ejecting a desired liquid by generation of bubble occurring when thermal energy is exerted on the liquid and to a head cartridge and a liquid ejecting device incorporating the liquid ejecting head.
More specifically, the present invention relates to a liquid ejecting head capable of replaceably being mounted on a plurality of devices and to a head cartridge and a liquid ejecting device incorporating the liquid ejecting head.
The present invention is the invention that can be applied to liquid ejecting heads having movable members arranged to be displaced by use of the generation of bubble, and the like.
The present invention is the invention applicable to equipment such as a printer, a copying machine, a facsimile machine having a communication system, a word processor having a printer portion or the like, and an industrial recording device combined with one or more of various processing devices, with which recording is effected on a recording medium such as paper, thread, fiber, textile, leather, metal, plastic material, glass, wood, ceramic material, and so on.
It is noted here that xe2x80x9crecordingxe2x80x9d in the present invention means not only provision of an image having meaning, such as characters or graphics, on a recorded medium, but also provision of an image having no meaning, such as patterns, on the medium.
2. Related Background Art
One of the conventionally known recording methods is an ink jet recording method for imparting energy of heat or the like to ink, using a heat generating element as an energy generating element, so as to cause a state change accompanied by a quick volume change of ink (generation of bubble), thereby ejecting the ink through an ejection outlet by acting force based on this state change, and depositing the ink on a recorded medium, thereby forming an image, which is so called as a bubble jet recording method. A recording apparatus using this bubble jet recording method is normally provided, as disclosed in the bulletin of U.S. Pat. No. 4,723,129 etc., with ejection outlets for ejecting the ink, ink flow paths in communication with the respective ejection outlets, and electrothermal transducers as energy generating means for ejecting the ink located in the ink flow path.
Another known method is ink jet ejection with a piezo-element as an energy generating element to eject ink by mechanical displacement of the piezo-element.
Particularly, the bubble jet recording method permits high-quality images to be recorded at high speed and with low noise and in addition, because a head for carrying out this recording method can have the ejection outlets for ejecting the ink as disposed in high density, it has many advantages; for example, high-resolution recorded images or even color images can be obtained readily by compact apparatus. Therefore, this bubble jet recording method is used in many office devices including printers, copiers, facsimile machines, and so on in recent years and further is becoming to be used for industrial systems such as textile printing apparatus.
With spread of use of the ink jet technology such as the bubble jet technology in products in wide fields, a variety of demands described below are increasing these years.
Especially, in the case of the conventional ink jet devices, the most of them allowed fixed voltage and current of electric energy to be received by the ink jet head mounted in the device, so that the mountable ink jet head was fixed for every ink jet device. There were proposals of some ink jet heads capable of being mounted on plural devices, but in such cases, the devices were arranged to supply common energy to the ink jet heads.
It was, however, not possible to apply a common head to devices different in energy quantity supplied to the head, for example, to a plurality of devices of different supply voltages.
Especially, under such circumstances that energy saving of device itself was intended as also in recent years, there was a problem to be solved that when a head compatible with a device designed in an energy-saving arrangement was attempted to be applied to another device produced without design of such energy-saving arrangement, the head did not work well.
Returning to the principle of liquid droplet ejection, some of the inventors reviewed the fundamental ejection characteristics of the conventional method for ejecting the liquid by forming the basically conventional bubble (especially, the bubble generated upon film boiling) in the liquid flow path, and proposed the liquid ejecting method for arranging the movable member so as to face the bubble generation region and for positively controlling the bubble, thereby greatly improving the ejection efficiency etc.
A novel ink jet head employing such a liquid ejecting method with improved ejection efficiency can achieve stable ejection performance of ink by lower power than the conventional ink jet heads. Therefore, printers ready for the novel ink jet head permit driving voltage for ejection of ink to be set lower, thereby achieving power saving. However, printers ready for the conventional ink jet heads had a problem that they were unable to use the novel ink jet head, because of the difference in driving power.
In order to allow mounting of the both conventional ink jet head and novel ink jet head with improved ejection efficiency, it is also conceivable to provide a plurality of power supply systems inside a recording apparatus so as to be ready for future ink jet heads of lowered driving power, but it is not preferable because of problems of increase in cost and increase in the size of apparatus.
It is also a subject of the present invention to enable a liquid ejecting head with high ejection efficiency capable of achieving energy saving to be mounted on various types of devices.
A first object of the present invention is to provide a liquid ejecting head and a head cartridge capable of performing good ejection, that can be mounted on devices mutually different in quantity of electric energy supplied to the liquid ejecting head.
A second object of the present invention is to provide a liquid ejecting head etc. applicable to various devices by improving the novel liquid ejecting head with increased ejection efficiency and ejection pressure, based on basic control of the generated bubble.
A third object of the present invention is to provide a liquid ejecting head etc. that can adjust the electric energy received from a device on which the head is mounted, to an appropriate energy quantity.
Typical features of the present invention for achieving the above objects are as follows.
The present invention provides a liquid ejecting head comprising an ejection outlet for ejecting a liquid, a liquid flow path in fluid communication with the ejection outlet, and an ejection energy generating element provided corresponding to the liquid flow path and arranged to receive an electric signal to generate ejection energy,
the liquid ejecting head having energy adjusting means for adjusting a quantity of energy supplied from the outside to the liquid ejecting head and utilized as said electric signal.
The present invention also provides a liquid ejecting head that can be replaceably mounted on a plurality of devices.
The present invention also provides a liquid ejecting head in which the foregoing ejection energy generating element is a heat generating element, which supplies thermal energy to the liquid supplied into the liquid flow path to generate a bubble therein and to eject the liquid through the ejection outlet by pressure upon generation of the bubble.
The present invention also provides a liquid ejecting head in which the foregoing energy adjusting means is means for converting a voltage of the aforementioned energy.
The present invention also provides a liquid ejecting head for ejecting ink as the liquid.
The present invention also provides a head cartridge comprising the liquid ejecting head constructed in either one of the above configurations, and a liquid container for reserving a liquid to be supplied to the liquid ejecting head.
The present invention also provides a liquid ejecting device comprising the liquid ejecting head constructed in either one of the above configurations, and energy supplying means for supplying the aforementioned energy to the liquid ejecting head.
The present invention also provides a liquid ejecting head comprising an ejection outlet for ejecting a liquid, a heat generating element for supplying heat to a liquid to generate a bubble in the liquid, and a movable member disposed so as to face said heat generating element, having a free end on the ejection outlet side, and arranged to displace said free end, based on pressure resulting from generation of the bubble, thereby guiding said pressure to the ejection outlet side,
the liquid ejecting head having energy adjusting means for adjusting a quantity of energy supplied from the outside to said liquid ejecting head and utilized as an electric signal applied to said heat generating element.
The present invention also provides a liquid ejecting head in which the aforementioned energy adjusting means is means for adjusting a voltage of said energy.
The present invention also provides a liquid ejecting head in which the free end of said movable member is located downstream of a center of an area of said heat generating element.
The present invention also provides a liquid ejecting head in which said bubble is a bubble generated when film boiling occurs in the liquid by the heat generated by the heat generating element.
The present invention also provides a liquid ejecting head in which said movable member is of a plate shape.
The present invention also provides a liquid ejecting head in which said movable member is constructed as a part of a partition wall disposed between a first flow path and a second flow path.
The present invention also provides a liquid ejecting head in which the voltage converting means is constructed by use of a voltage divider.
The present invention also provides a liquid ejecting head in which the voltage converting means is constructed by use of a DC-DC converter.
The present invention also provides a head cartridge comprising the liquid ejecting head constructed in either one of the above configurations, and a liquid container for reserving a liquid to be supplied to the liquid ejecting head.
The present invention also provides a liquid ejecting device comprising the liquid ejecting head constructed in either one of the above configurations, and
energy supplying means for supplying said energy to the liquid ejecting head.
The present invention also provides a recording system comprising:
means for replaceably mounting said liquid ejecting head;
said liquid ejecting head outputting an ID signal indicating a type of the liquid ejecting head mounted,
said liquid ejecting device having controlling means for identifying the type of the liquid ejecting head from presence or absence of said ID signal and output contents thereof and for controlling a width of a pulse signal supplied to said liquid ejecting head in accordance with the identified type.
[Function]
The above-stated configurations enable the head to be mounted on various devices, even in the case wherein the head is mounted on the plural devices arranged to supply different electric energies, because the head itself adjusts the energy received from the device side.
In addition, the liquid ejecting method, head, etc. according to the present invention, based on the very novel ejection principle, can attain the synergistic effect of the bubble generated and the movable member displaced thereby, so that the liquid near the ejection outlet can be ejected efficiently, thereby improving the ejection efficiency as compared with the conventional ejection methods, heads, and so on of the bubble jet type. For example, the most preferable form of the present invention achieved the breakthrough ejection efficiency two or more times improved.
With the head of the invention described, therefore, the head can be driven by lower energy than heretofore.
In order to provide the ejecting head of improved ejection efficiency with capability of replacing the conventional heads so as to be mounted on the conventional devices, it has the adjusting means for adjusting the energy received by the head. Since the head is capable of ejecting the liquid by lower energy because of the high ejection efficiency, the adjusting means is for adjusting (or lowering) the energy supplied to the recording head when the head is mounted on the recording apparatus in the same manner as the conventional heads, for allowing the head of the invention to replace the conventional heads. The above-stated configuration permits the ejecting head of the present invention to be handled in the same way as the conventional heads.
The other effects of the present invention will be understood from the description of the embodiments.
The terms xe2x80x9cupstreamxe2x80x9d and xe2x80x9cdownstreamxe2x80x9d used in the description of the invention are defined with respect to the direction of general liquid flow from a liquid supply source through the bubble generation region (or the movable member) to the ejection outlet or are expressed as expressions as to this structural direction.
Further, the xe2x80x9cdownstream sidexe2x80x9d of the bubble itself represents an ejection-outlet-side portion of the bubble which directly functions mainly to eject a liquid droplet. More particularly, it means a downstream portion of the bubble in the above flow direction or in the above structural direction with respect to the center of the bubble, or a bubble appearing in the downstream region from the center of the area of the heat generating element.
A xe2x80x9csubstantially sealedxe2x80x9d state used in the description of the invention generally means a sealed state in such a degree that while a bubble grows, the bubble is kept from escaping through a gap (slit) around the movable member before displacement of the movable member.
The xe2x80x9cpartition wallxe2x80x9d stated in the invention may mean a wall (which may include the movable member) interposed to separate the region in direct fluid communication with the ejection outlet from the bubble generation region in a wide sense and, more specifically, means a wall for separating the liquid flow path including the bubble generation region from the liquid flow path in direct fluid communication with the ejection outlet, thereby preventing mixture of the liquids in the respective liquid flow paths, in a narrow sense.